var button1  = document.getElementById('anliu');
var button1  = document.getElementById('button1');
var Div1 = document.getElementById('Div1');
button1.onclick = function(){
    var val = Div1.style.display;
    if(val == 'none'){
        Div1.style.display = 'block'; //显示
		anliu.className='box-box';
    }else{
        Div1.style.display = 'none'; //隐藏
		anliu.className='box';
    }
}